A patent literature 1 shown below describes a bass reverse speaker device. This speaker device has a speaker unit and a passive vibrating body (passive radiator), a vibration system without a driving system such as a magnetic circuit from the speaker unit, mounted on or in a single cabinet. It can have a preferable low-frequency performance compared to a speaker device mounting a speaker unit on a sealed cabinet.
This speaker unit uses a typical dynamic type speaker device. The dynamic speaker device, for example, as shown in FIG. 1, includes a frame 3J, a cone-shaped diaphragm 21J, an edge 4J through which the diaphragm 21J is supported by the frame 3J, a voice coil bobbin 610J applied to the inner periphery part of the diaphragm 21J, a damper 7J through which the voice coil bobbin 610J is supported by the frame 3J, a voice coil 611J wound around the voice coil bobbin 610J, a yoke 51J, a magnet 52J, a plate 53J, and a magnetic circuit having a magnetic gap in which the voice coil 611J is arranged. In this speaker device, when an audio signal is inputted to the voice coil 611J, the voice coil bobbin 610J vibrates by a Lorentz force developed in the voice coil 611J in the magnetic gap and the diaphragm 21J is driven by the vibration.